My X5 will run ok for a few miles then these code's will show up on my scan tool. I found the Y-Duct that is part of the air intake hose's had large cracks in between the rib's (small ribed section of the y-duct). I tryed to seal them with a silicon that I had used when I installed a [COLOR=blue !important][COLOR=blue !important]pellet [COLOR=blue !important]stove[/COLOR][/COLOR][/COLOR]. It does not slump & dry's flexible. I ran the car a little further this time before the code's came back. I removed the y-duct from the car this time & found 2 more small cracks in between the ribs. I have sealed with the same silicone again, & will let dry overnight.

Does anyone have any other idea's (if anything) that would set these code's. The P0171, & P0174 come up first & then within a few miles the rest of the fault code's show up.
I have ordered the new y-duct.

My X5 will run ok for a few miles then these code's will show up on my scan tool. I found the Y-Duct that is part of the air intake hose's had large cracks in between the rib's (small ribed section of the y-duct). I tryed to seal them with a silicon that I had used when I installed a [COLOR=blue !important][COLOR=blue !important]pellet [COLOR=blue !important]stove[/COLOR][/COLOR][/COLOR]. It does not slump & dry's flexible. I ran the car a little further this time before the code's came back. I removed the y-duct from the car this time & found 2 more small cracks in between the ribs. I have sealed with the same silicone again, & will let dry overnight.

Does anyone have any other idea's (if anything) that would set these code's. The P0171, & P0174 come up first & then within a few miles the rest of the fault code's show up.
I have ordered the new y-duct.

Thanks you in advance.
Jay
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The P0171 and P0174 are telling you the fuel system is "lean". These can be caused by bad O2 sensors and vacuum leaks. Check the OBD II codes online. The "300" series of codes are misfires, with the third digit telling you which cylinder. Could be your plug wires.

Those look like lean codes to me. Does check engine light come on? I would think replacing the air duct should do it for ya. You might make sure you check all your vacuum hoses too. Same type of problem I had in the past. The above is what worked for me.

Was this reply in the wrong thread? The OP has a 3.0i with the common air duct tear to the idle control valve... As for his random cylinder missfires registered in all cylinders, hopefully it is related.

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Report back after you've replaced the Y duct. I'd also suggest to reset the codes and/or remove tha battery cables and touch them together overnight as a poorman's way to make the ECU relearn itself. After a couple days of driving, if you've still got a CEL, then it might be time for another visual inspection or a simple smoke machine test...leaks can sometimes be hard to find w/ the naked eye.